The present invention relates to a valve for the interception and the regulation of a fluid flow with a fixed tubular sealing element.
More particularly, the present invention relates to a valve acting as a gate valve or as a cock, which intercepts and regulates the fluid flow within a pipeline, essentially by means of a fixed flexible tubular sealing element.
Gate valves and cocks are mainly employed in order to intercept fluid streams along a pipe; the action of such valves and cocks is principally that of allowing the fluid flow to occur or that of interrupting such flow, but such devices can also act as flow rate regulation devices though not in an optimal way.
Cocks are the most employed devices for smalll-size pipes, both in the industrial and in the civil field, for instance in the case of plumbing systems. Cocks can be manually operated and they generally have a sealing element of the plug type bearing one or more passageways or through-holes, which sealing element can be rotated within a housing or seat so that said passageways can be aligned or not with the ports in the valve body through which the fluid flows.
Gate valves are more often employed in the case of high flow rate pipes and in industrial applications, and they can be operated either manually or by means of a motor; the sealing member in such valves is made up of a wedge-shaped baffle that runs transversally with respect to the body of the valve and to the pipe; its shift is generally obtained by screwing the stem on a nut screw, through a handwheel in the case of manual operation.
In both the abovementioned solutions, the whole power for reducing or intercepting the fluid flow by opposing the pressure of the fluid itself is to be supplied by the member which drives the sealing element, i.e. such power is to be supplied from the outside; particularly in the case of gate valves of large sizes, high efforts are needed for operating the handwheel by hand or otherwise high starting torques and quite high consumption are necessarily met with if a motor is employed for operating the valve.
Moreover, the bodies of said valves are generally bulky and quite costly both as regards their production and their maintenance.